Noncontrolling interests (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Apr. 01, 2012
Balance	$ 813,719,000
Consolidated net income	19,604,000	18,608,000
Other Comprehensive Income	(12,500,000)
Dividends declared	(1,800,000)
Dividends paid to non-controlling interest	(486,000)	0
Employee benefit transactions	2,700,000
Income tax benefit arising from employee stock option	700,000
Purchase of common stock	(9,400,000)
Stock based compensation	200,000
Balance	812,759,000
Common Stock [Member]
Balance	4,700,000
Consolidated net income	0
Other Comprehensive Income	0
Dividends declared	0
Dividends paid to non-controlling interest	0
Employee benefit transactions	0
Income tax benefit arising from employee stock option	0
Purchase of common stock	0
Stock based compensation	0
Balance	4,700,000
Additional Paid-in Capital [Member]
Balance	345,900,000
Consolidated net income	0
Other Comprehensive Income	0
Dividends declared	0
Dividends paid to non-controlling interest	0
Employee benefit transactions	2,700,000
Income tax benefit arising from employee stock option	700,000
Purchase of common stock	0
Stock based compensation	200,000
Balance	349,500,000
Retained Earnings [Member]
Balance	1,032,900,000
Consolidated net income	18,800,000
Other Comprehensive Income	0
Dividends declared	(1,800,000)
Dividends paid to non-controlling interest	0
Employee benefit transactions	0
Income tax benefit arising from employee stock option	0
Purchase of common stock	0
Stock based compensation	0
Balance	1,049,900,000
Accumulated Other Comprehensive Income (Loss) [Member]
Balance	(51,200,000)
Consolidated net income	0
Other Comprehensive Income	(12,000,000)
Dividends declared	0
Dividends paid to non-controlling interest	0
Employee benefit transactions	0
Income tax benefit arising from employee stock option	0
Purchase of common stock	0
Stock based compensation	0
Balance	(63,200,000)
Treasury Stock [Member]
Balance	(541,900,000)
Consolidated net income	0
Other Comprehensive Income	0
Dividends declared	0
Dividends paid to non-controlling interest	0
Employee benefit transactions	0
Income tax benefit arising from employee stock option	0
Purchase of common stock	(9,400,000)
Stock based compensation	0
Balance	(551,300,000)
Noncontrolling Interest [Member]
Balance	23,300,000
Consolidated net income	900,000
Other Comprehensive Income	(500,000)
Dividends declared	0
Dividends paid to non-controlling interest	(500,000)
Employee benefit transactions	0
Income tax benefit arising from employee stock option	0
Purchase of common stock	0
Stock based compensation	0
Balance	$ 23,200,000